INTRODUCTION
Injection of a foreign protein into the animal body leads to certain well defined phenomena which should be familar to all. If sensitization, following a previous dose, be present, anaphylactic shock may result. Otherwise one expects, first, a latent period with no outward manifestation but during which it is believed that the protein is undergoing chemical change into less complex and more stable substances, and, second, a rise of temperature with an increase of the neutrophil polymorphonuclear white cells of the blood. If the injection be subcutaneous or intramuscular, the sequels are mild and last over a day or more; if the injection is intravenous, they are relatively violent and subside in a few hours. Vaughan1 has considered the excess heat production as being due to three factors; (1) the unusual activity of the cells supplying the proteolytic enzyme; (2) cleavage of the foreign protein; (3) the destructive reaction